As you can see in the diagram below, the P4X266's North Bridge provides support for regular SDRAM and DDR SDRAM. The DDR memory controller is the same as the one found in VIA's latest revision of the KT266 chipset, the KT266A. This controller supports up to 4GB 200/266MHz DDR SDRAM. The P4X266 chipset also uses the same V-Link interface and AGP 4x controller that we saw in the KT266 chipset.
The P4X266 chipset is compatible with both the Socket 423 and Socket 478 form factors. The newer Socket 478 form factor will be used for future Pentium 4 processors such as the soon to be released Northwood based Pentium 4. The P4X266 motherboards we are testing today both feature the Socket 478 design.
Adding to the list of similarities of the KT266 chipset, the P4X266 features the VT8233 South Bridge. This South Bridge has a built in Ethernet controller, three USB controllers, two ATA100/66/33 controllers and support for an integrated 56k modem. The VT8233 also features 6 channel AC-97 sound. The South Bridge and North Bridge communicate through an 8bit V-Link bus that can transfer at speeds of up to 266MB/sec.
We have been given the opportunity to review two P4X266 motherboards. These are the Shuttle AV40R and the ACorp 4VPX266A. Before we move on to the benchmarks, lets take a look at each board individually.